DECOMPOSITION OF LITTER AND SOIL ORGANIC-MATTER - CAN WE DISTINGUISH A MECHANISM FOR SOIL ORGANIC-MATTER BUILDUP

This synthesis paper presents a model for estimating the buildup of so il organic matter in various types of coniferous forests. The knowledg e used was obtained from a well-studied forest with good litterfall da ta, decomposition information and validation measurements of the soil organic matter layer. By constructing a simple model for litterfall, a nd the information on maximum decomposition levels for litter, we coul d estimate the annual increase in soil organic matter and extend this to encompass stand age. The validation measurement and the estimated a mount of soil organic matter differed by about 8 or 26% over a 120-yr period, depending on the litterfall model. The estimated increased sto rage of soil organic matter as a consequence of climate change was fou nd to be drastic. We thus found that the soil organic matter layer wou ld grow about four times as fast as a result of the needle component o nly. This estimate was based on a comparison between latitudes with a difference of 17-degrees.